Goofs: We hear some strange, loud noises in space [although given
it's an audio adventure about big bangs, perhaps this is excusable].

Technobabble: There's some malfunctioning of the TARDIS' relative
dimensional computer [which, the Doctor explains 'means that the steering's
gone haywire']. Other features include a chronometric astrometer, while
cosmo-retrozine enables the TARDIS to free itself from the proto-Earth's
gravitational pull.

The 'compressive telesight' "lets the events of millions of years
pass before you in minutes".

Double Entendres: 'You know how tactful one must be with the
low continuum resolution.'

'Look, Sarah, look at that enormous body; we're held in the pull of
it.'

Dialogue Disasters: 'At this speed we're getting loster and loster,
thousands and thousands more miles every second.'

'Insolent ignoramus! Take that!'

Dialogue Triumphs: The Doctor shows off about his travels 'Everest?
Stalagmite!'

Continuity: Given her longing to see the place, it seems to have
been some time since Sarah was last on Earth, or at least in her own time.
The TARDIS has a bubble-like two-person capsule which enables both the
Doctor and Sarah to witness the creation of Earth - it requires 'atmosphere
injection' [probably some form of life support, given that after 'injection'
a humming sound can be heard].

Megron is High Lord of Chaos and Chief of the Carions, Lords of Chaos
and 'enemies of the Time Lords down the endless ages'. Presumably they
have less power than the Time Lords now, as the Doctor easily defeats him
by Telepathic Will Deployment [perhaps this is something like the mind-wrestling
seen in 'The Brain of Morbius'?].

Location: The TARDIS, and Earth's outer atmosphere (or thereabouts)
4,500 million years before present, and various points (three further stops
'millions' of years thence) afterward.

Weird. And educational, probably. On the whole the
episode, running at just over 19 minutes has a rather inconsequential feeling
to it, but given the lack of real plot, it's probably just long enough.
For an adventure that has as much to do with Doctor Who's ongoing story
as Search Out Space, this is best taken at face value.